Chitosan-based intragastric delivery of cefuroxime axetil: Development and in-vitro evaluation of mucoadhesive approach

Figures & data

Table I. Levels and values for independent factors in Box-Behnken experimental design

	Coded Levels			Actual Values
Trial No.	X1	X2	X3	X1^2	X2^2	X3^2
MB 01	1	0	-1	4	6	5
MB 02	0	-1	1	3	4	7.5
MB 03	0	0	0	3	6	6.25
MB 04	1	1	0	4	8	6.25
MB 05	0	1	1	3	8	7.5
MB 06	0	0	0	3	6	6.25
MB 07	1	0	1	4	6	7.5
MB 08	-1	0	1	2	6	7.5
MB 09	0	0	0	3	6	6.25
MB 10	-1	-1	0	2	4	6.25
MB 11	-1	1	0	2	8	6.25
MB 12	0	0	0	3	6	6.25
MB 13	1	-1	0	4	4	6.25
MB 14	0	0	0	3	6	6.25
MB 15	-1	0	-1	2	6	5
MB 16	0	-1	-1	3	4	5
MB 17	0	1	-1	3	8	5
MB 18$	1	-	-1	4	-	5

²Actual value indicate concentration of solution/dispersion in % w/v.

$Placebo trial (Control) batch without CXA content, not a part of Box-Behnken design.

Figure 1. Setup Representing Test for Mucoadhesive Strength of Microbeads.

Figure 2. FTIR Spectra of (A) Unexposed CXA + Excipients blend, (B) Exposed CXA + Excipients blend, (C). Excipients blend without CXA and (D) Untreated CXA.

Figure 3. DSC Th ermograms of (A) Untreated CXA, (B) Excipients blend without CXA, (C) Exposed CXA + Excipients blend and (D) Unexposed CXA + Excipients blend.

Figure 4. XRPD Patterns of Pure CXA and CCXA Microbead Formulation.

Figure 5. Single Factor Correlation between Independent and Response Variables.

Table II. Experimental design and corresponding responses in terms of dependent variables and evaluation parameters.

Trial No.	Y^a (%)	EE^a (%)	MS^a (%)	T90^# (h)	Drug Content^a (%)	Microbead Size^$ (µm)	Swelling Index^a
MB 01	75.4 ± 0.12	81.9 ± 1.55	99.3 ± 0.94	3	98.1 ± 0.15	789 ± 8.55	452 ± 10.34
MB 02	88.2 ± 3.56	86.4 ± 1.68	92.0 ± 1.62	4	97.3 ± 0.29	802 ± 8.94	425 ± 23.74
MB 03	91.0 ± 0.27	87.3 ± 3.58	94.7 ± 1.88	4	99.6 ± 0.74	760 ± 31.02	430 ± 9.32
MB 04	84.6 ± 3.95	88.8 ± 6.32	96.7 ± 3.39	5	99.6 ± 0.91	849 ± 11.65	335 ± 2.46
MB 05	96.5 ± 0.22	99.2 ± 4.76	90.3 ± 0.94	8	97.0 ± 0.11	812 ± 18.49	388 ± 26.17
MB 06	93.5 ± 0.94	88.5 ± 3.56	92.0 ± 4.32	4	100.3 ± 0.68	731 ± 19.03	405 ± 31.89
MB 07	78.3 ± 2.98	85.6 ± 0.94	95.3 ± 3.39	4	98.9 ± 1.54	793 ± 15.28	480 ± 16.37
MB 08	88.2 ± 3.04	85.4 ± 5.21	80.3 ± 8.89	5	97.4 ± 2.88	711 ± 17.22	296 ± 8.91
MB 09	92.4 ± 3.02	90.2 ± 3.59	92.7 ± 1.63	4	99.6 ± 1.03	755 ± 13.69	399 ± 15.85
MB 10	78.4 ± 2.28	78.9 ± 4.87	86.7 ± 5.24	3	98.0 ± 3.25	754 ± 19.05	479 ± 11.87
MB 11	92.9 ± 1.17	90.3 ± 3.52	78.3 ± 5.22	8	97.8 ± 2.07	801 ± 22.48	334 ± 29.47
MB 12	90.6 ± 0.95	88.8 ± 2.29	92.3 ± 7.11	4	99.7 ± 0.44	745 ± 29.04	420 ± 22.39
MB 13	76.1 ± 0.87	82.2 ± 2.01	96.7 ± 4.32	2	98.6 ± 0.59	780 ± 30.65	471 ± 9.64
MB 14	90.5 ± 4.68	87.5 ± 8.73	93.0 ± 1.88	4	100.8 ± 0.12	728 ± 18.23	411 ± 8.47
MB 15	83.7 ± 3.62	80.5 ± 8.94	88.0 ± 8.64	4	100.5 ± 0.28	805 ± 8.38	368 ± 18.39
MB 16	85.5 ± 5.56	80.5 ± 3.04	98.7 ± 0.94	4	99.7 ± 1.05	782 ± 29.33	387 ± 14.28
MB 17	95.3 ± 0.99	98.8 ± 3.57	96.3 ± 0.94	8	100.2 ± 1.18	820 ± 10.34	402 ± 32.47
MB 18	93.4 ± 2.82	94.9 ± 4.21	98.0 ± 1.68	2	2	704 ± 17.94	427 ± 28.29

^ais the mean of 3 values ± SD; ^#is the time point during release profile done on 6 dosage forms per batch; ^$is the mean of 20 values ± SD.

Table III. ANOVA for response surface quadratic models correlating different response variables.

	Y1 (Yield)			2 (EE)			Y3 (MS)			Y4 (T90)
Terms	EC	F value	Prob > F	EC	F value	Prob > F	EC	F value	Prob > F	EC	F value	Prob > F
b0	91.20	29.07	0.0001	88.00	14.14	0.0010	92.80	78.74	0.0001	4.00	38.20	0.0001
X1	-3.50	36.49	0.0005	0.38	0.28	0.6107	6.75	481.42	0.0001	-0.75	31.50	0.0008
X2	5.00	74.47	0.0001	6.13	75.71	0.0001	-1.50	23.77	0.0018	2.00	224.00	0.0001
X3	1.50	6.70	0.0360	2.00	8.07	0.0250	-3.00	95.09	0.0001	0.25	3.50	0.1036
X1X2	-1.50	3.35	0.1099	-1.50	2.27	0.1756	2.00	21.13	0.0025	0.50	7.00	0.0331
X1X3	-0.50	0.37	0.5610	-0.25	0.063	0.8089	1.00	5.28	0.0551	0.000	0.000	1.0000
X2X3	-0.50	0.37	0.5610	-1.25	1.58	0.2495	0.000	0.000	1.0000	0.000	0.000	1.0000
X1^2	-9.35	137.06	0.0001	-5.75	35.12	0.0006	-3.65	74.09	0.0001	-0.75	16.58	0.0047
X2^2	0.65	0.66	0.4425	2.25	5.38	0.0535	-0.15	0.13	0.7340	1.25	46.05	0.0003
X3^2	-0.85	1.13	0.3225	0.50	0.27	0.6222	1.35	10.14	0.0154	0.75	16.58	0.0047
R^2	0.9739			0.9478			0.9902			0.9800
Adj R^2	0.9404			0.8808			0.9776			0.9544
Pred	0.7192			0.3284			0.9181			0.6808
R^2

Model Terms having Prob > F values < 0.0500 indicate that these have significant effect on the response variables; EC and F are the Estimated Coefficient and fit test values corresponding to model terms, respectively.

Table IV. Details of constraints set for RSM, and optimized formula proposed by Design Expert^® software.

RSM Optimization Process Parameters
Factors	Chitosan	CXA	STP	Y (%)	EE (%)	MS (%)	T90 (h)
Factor type	Independent	Independent	Independent	Dependent	Dependent	Dependent	Dependent
Lower Limit	2	4	5	75	78	78	2
Higher Limit	4	8	7.5	96	99	99	8
Goal set	in range	in range	minimum	maximum	maximum	maximum	maximum
Importance*	4	4	4	4	4	5	5
RSM Optimization Solution
Factor value	3.00^$	8.00^$	5.00^$	94.98^#	96.12^#	95.53^#	7.75^#

*In the range of 1 to 5 and 5 being highest.

^$Suggested concentrations of solution/dispersion to be utilized as a result of RSM in %w/v.

^#Predicted values of the outcome for response variables.

Figure 6. Response Graphs and Contour Plots for % Yield and Entrapment Efficiency.

Figure 7. SEM Images of Optimized Microbeads Formulation A, B, C (MB 17) and Control Microbead Formulation D, E, F (MB 18).

Figure 8. Response Graphs and Contour Plots for % MS and T90%.

Figure 9. Dissolution Profile of Optimized Formulation (MB 17) in Diff erent Acidic Media.